Paper 2026/1013

Sequence-Level Security for Active Weighted Signature Reconfiguration

Sunghyeon Jo, Georgia Institute of Technology
Abstract

Active weighted threshold signatures support dynamic changes to signer weights, thresholds, and committee membership. We show that local validity of weighted update operations is not a compositional security abstraction: a sequence of individually valid updates can move an initially sub-threshold coalition into an authorized reachable state. We introduce rank-exposure guards, a compiler that enforces a reconstruction-safety invariant over live, stale, derivative, public, and transient signing material. The compiler wraps ledger-sound one-step update engines with atomic activation and old-epoch digest-bound transition certificates, lifting fixed-state weighted unforgeability and update soundness to sequence-level active unforgeability. We instantiate the compiler as REG-ADAPT, a guarded GLI reconfiguration scheme built around ADAPT-style local updates, and implement it on top of the public ADAPT Go artifact. Our evaluation shows that the artifact detects and rejects unsafe update sequences, while adding only microsecond-scale metadata and rank-audit overhead.

Metadata
Available format(s)
PDF
Category
Applications
Publication info
Preprint.
Keywords
Active weighted signatureWeighted threshold signatureDynamic threshold signatureShamir secret sharing
Contact author(s)
sjo65 @ gatech edu
History
2026-05-21: revised
2026-05-20: received
See all versions
Short URL
https://ia.cr/2026/1013
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2026/1013,
      author = {Sunghyeon Jo},
      title = {Sequence-Level Security for Active Weighted Signature Reconfiguration},
      howpublished = {Cryptology {ePrint} Archive, Paper 2026/1013},
      year = {2026},
      url = {https://eprint.iacr.org/2026/1013}
}
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